"It's safe to say that we don't fully understand why this approach works so well, but we'll take it and develop it and figure out the details as we go," Gerald Meyer, professor of chemistry in the Krieger School of Arts and Sciences at The Johns Hopkins University, said with a laugh.

The targets of the new technique, developed by Sherine Obare, a postdoctoral fellow in Meyer's lab, are organohalides, a class of compounds used in pesticides, pharmaceuticals, and manufacturing. They pose health risks to humans and have been linked to environmental problems like ozone depletion and climate change.

Obare's new approach combines an extremely thin film of titanium dioxide with a compound found in life known as hemin. After exposure to ultraviolet light, the hemin and titanium dioxide can break up organohalides at surprisingly high rates. Obare and Meyer will present results of tests of the new approach at 6 p.m. on Sept. 8 in the North Pavillion of the Javits Convention Center in New York at the 226th national meeting of the American Chemical Society.

Seventeen of the top 25 organic groundwater contaminants in urban areas are organohalides, according to a 1997 Environmental Protection Agency report. Organohalides are a class of organic compounds that include a halogen, a group of elements comprised of bromine, fluorine, iodine and chlorine. The compounds are very difficult to break down chemically. Some instances of organohalides in the environment today, for example, can be traced back to the dry cleaning industry of the 1920s and 1930s.

Meyer is director of the National Science Foundation-funded Collaborative Research Activities in Environmental Molecular Sciences
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Contact: Phil Sneiderman
prs@jhu.edu
410-516-7160
Johns Hopkins University
9-Sep-2003